Polyethylene is used in the production of various products and for example of blow molded products such as bottles and containers. Examples of such blow molded products include consumer/household containers such as detergent bottles, shampoo bottles, and the like; industrial containers such as carry cases for hardware/tools, containers for argricultural chemicals, photochemicals; and industrial parts.
Blow molding is accomplished by extruding molten polyethylene resin into a mold cavity as a parison or a hollow tube while simultaneously forcing air into the parison so that the parison expands, taking on the shape of the mold. The molten polyethylene cools within the mold until it solidifies to produce the desired molded product.
The blow molded products made from polyethylene or polyethylene blends offer relatively good strength and other performance properties. It is desirable that the final polyethylene or polyethylene blend product exhibits good physical properties such as good drop impact, stiffness and good environmental stress crack resistance (ESCR).
In our days it is desirable to attempt to recycle and reuse plastic materials, commonly known as post consumer resin (PCR). However, such recycling in attempts to make containers such as bottles, resulted in the obtaining of poor mechanical properties in the final products obtained. In particular, the containers produced from recycled polyethylene may show poor environmental stress crack resistance (ESCR).
To enhance said properties, it is known to blend such post consumer resin with virgin material. Such a process is for example described in WO2012/139967 where HDPE detergent packaging waste was selected for its ESCR properties (ESCR 100% ranging from 20 to 60 hours) and blended with virgin HDPE. However the use of detergents bottles which are colourful and have contained chemical products resulted in the production of articles containing recycled polymer having good mechanical properties but showing a grey colour and being smelly.
EP0654496 and U.S. Pat. No. 5,693,391 disclose a lightweight plastic container having stress crack resistance and comprising at least one layer comprising post consumer milk resin blended with virgin HDPE copolymer resin. The virgin HDPE copolymer resin selected has a density of at least 0.94 g/mL and a melt index of less than 0.5 g/10 min. However the results obtained are not entirely satisfactory and it is desirable to improve them.
There remains a need in the industry to better valorise plastic waste. Thus it is desirable to develop a polyethylene composition comprising recycled material, and blow moulded products produced from that composition, that shows at the same time good mechanical properties such as a good rigidity and ESCR, with good processability for applications such as blow moulding application.
There remains also a need in the industry to develop a polyethylene composition comprising recycled material, and blow moulded products produced from that composition, that shows at the same time good mechanical properties such as a good rigidity and ESCR, with good processability for applications such as blow moulding application, and with good properties regarding odour and colour.